Preheat oven to 200 degrees. (If making multiple omelets store the cooked ones on a baking sheet in the oven until all are finished and you're ready to serve.)
Heat oil in a nonstick pan on medium heat. Add, diced onion, kale, and sliced mushrooms. Saute for 3 minutes over medium heat.
Pour the eggs into the pan. As the eggs set around the edge of the pan, with a spatula, gently lift the egg to allow uncooked egg to flow underneath. When eggs are almost set on the surface but still look moist, add the cheese. Slip the spatula under the omelet and fold over.
In a nonstick pan over medium heat brown the chicken sausage on both sides. In the meantime toast the bread.
Serve the omelet with toast, chicken sausage, and sliced pineapple on the side.